A mute has been known which is used by being attached to a bell for the purpose of reducing the volume of sound produced by a wind instrument during playing. A bell of a wind instrument refers to a portion which is close to an outlet for exhaled air where the diameter of a pipe of the wind instrument gradually increases in order to increase the volume of sound. In the specification of the present invention, the direction from the end of the bell of the wind instrument toward the inside thereof is referred to as “in rear”, and the direction from the end of the bell of the wind instrument away from the bell is referred to as “in front”.